Investigating the origin and authenticity of Victoria Cross medals using X-ray fluorescence spectrometry

The Victoria Cross is the United Kingdom's premier military award for bravery, presented for gallantry during active operations. Since its inception in 1856 just 1358 have been awarded, and, due to their rarity and historic interest, have become highly prized amongst private and public collections. Unresolved, however, is a debate about the source material of the medals. Some authorities adhere to a traditional belief that all medals have been cast from the bronze of guns captured from the Russians at Sebastopol. Furthermore, controversy is attached to the authenticity of some VCs. In this study we used X-ray fluorescence spectrometry data to compare the metal compositions of 100 Victoria Crosses, covering 7% of those ever issued. Using Gaussian mixture modelling we identify that Victoria Crosses fall into four distinct clusters, confirming that the primary split occurred between medals issued prior to and after 1914. Using these data we investigate the potential of X-ray fluorescence to inform the study of medals whose authenticity have been queried, showing some have unusually similar compositions to other VCs. This paper highlights how X-ray fluorescence data in conjunction with clustering approaches can be used to effectively and non-destructively investigate the authenticity and history of Victoria Crosses.